Fix performace regression due to missed peephole optimization

src/codegen-arm.cc

Index: src/codegen-arm.cc
===================================================================
--- src/codegen-arm.cc	(revision 282)
+++ src/codegen-arm.cc	(working copy)
@@ -948,6 +948,7 @@
     ASSERT(var()->mode() != Variable::DYNAMIC);
 
     Label exit;
+    bool skipped_write = false;
     if (init_state == CONST_INIT) {
       ASSERT(var()->mode() == Variable::CONST);
       // Only the first const initialization must be executed (the slot
@@ -957,6 +958,7 @@
       masm->ldr(r2, ArmCodeGenerator::SlotOperand(masm, scope, this, r2));
       masm->cmp(r2, Operand(Factory::the_hole_value()));
       masm->b(ne, &exit);
+      skipped_write = true;
     }
 
     // We must execute the store.
@@ -981,7 +983,9 @@
       masm->mov(r3, Operand(offset));
       masm->RecordWrite(r2, r3, r1);
     }
-    masm->bind(&exit);
+    // If we did not jump over the assignment, we do not need to bind the
+    // exit label.  Doing so can defeat peephole optimization.
+    if (skipped_write) masm->bind(&exit);

[iposva, 2008/09/11 18:25:11]

Why do you introduce a separate variable for testing (init_state == CONST_INIT)?
In my opinion that is more confusing. Same for ia32.

   }
 }